Telephone party-line system.



m. 810,345, PATENTE JAN, 16, 1906... A, F. PGULE @L P, B. HALL.

TELEPHONE PARTY LINE SYSTEM. APPLIGAQON H LED 00T.1a,1902.

4 SHEETS-SHEET l.

10.810,345, 4 MT1-:MED JAN.1,6, 1906.` A. F. .POOLE @L F. B. HALL.

TELEPHONE PARTY LINE SYSTEM.

APPLICATO'N FILED 0C'T.13,1902.

4 SHEETS-SHEET 2.

1255125- {NEVI-hm l NI). 810,345. PATENTD JAN. 1'6, 1906. A. I'. POOLE LI'. B. HALL. TELEPHONE PARTY LINE SYSTEM.

4 APPLICATION IILBD OGT. 13,1902.

4 SHEETS-SHEET No. 810,345. PATENTED JAN. 16, 1906.

A. E. POOLE & E. B. HALL.

-TELEPHONE PARTY LINE SYSTEM.

APPLICATION FILED 00T.1s,1902.

.4 SHEETS-SHEET 4.

WIUEEEEE-.u IULETLLH A Darla? UNITED sTATEs PATENT OEEICE.

'ARTHUR -EQPooLEAND 'FRANK B. HALL, or WHEELING, wEsT VIRGINIA.

A.ToV 'aLZL whom it coun/cern:I

ro companyingdrawings, forminga part of tb'is speciic ationfl invention,relatesto tele TELEPHONE PARTY-LINE SYSTEMI Be it known that we, ARTHURF.' PooLE liana FRANK- B. met, citizens of the United States, residingat Wheeling, in the countyfof Ohio and State of West Vilia,ha'veinvent'- ed a certain new and usefu Improvement in Telephone'Party-LineSystems, of which the following is a full, clear, concise, and exact'descriptiomf 'reference being Ahad to the achone partylinc stems,Aandmore particu arly to what .1 svstem includinga new selecting-circuitytermed Party line selective 'sysf tems; 7 l

The 'I cipal 4.objects of our invention are to provide a new and.improved party-line therefor and roved'switching mechanismitheifadjustment, and therefore zfo'ruse therewit and thereby toovercome 'the defects in the construction and operation of party-linesystems heretofore emp oyed. rtline systems of the pxllior art ma bedivide i* into two classes.' .ilasses the apparatus installed at asub--y rds'pond only to currents of a certain nature wit respect totheir strength or polarity', or both* Such systems arenecessarillydelicate in iable to get out ofoperative condition. Suchsystems,furthermoreyare necessarily limited' to a small number of stations oneach line. AThe other class of'party-line systems employ what is gen-verally known as step-by-step devices. In 'this class or' systemsstep-by-step mechanism is installed at each of- .the substations onaparty-line, the said mechanism being operated in synchronism withmechanism vat the centralstation. In 'such systems the -m'ech-v anism atall of the substations on anyone party-line must 'be operated at 'thesametime, thereby requiring a very powerful current. A further defect inmanyv of these step-bystep party-line systems has been,. that on accountof the complication ofthemechanism employed, it was very subject toderangement, and a'further. ditiicultyarose in that the derangement ofthe mechanism of any one station was liable to throw out of op@ all -t eerative condition the mechanism at other stations on the same line, sucha general derangement often requiring the personal attention of anexpertat each of the statiqns on a line.

Qur invention contemplates animpi'oyed ,Specification of Letters Patent.Application iled October 13, 1 902. Serial No. 12'l ,113.

invention we one of t ese Patentedl Jan. 1.6, 1906.

'system in whichv these-defects and diiiiculties are overcome; Inaccordance with our rovide a selective part line systemin which theapparatus instal ed at each ofthe substations on a line is operatedindividually, the apparatus at the substations being operatedsuccessively. This operation di but one set of ap aratus at a timeenables the operationo the system to be accomplished with a relativelysmall amount'. of current or strength of current.

The system-may be employedwith any partyline without requiring theinstallation of new telephone apparatus, the system being Wellada tedfor use with any type of telephone an telephone-circuit.

l Another advantage obtained from the use of the system of our inventionconsists .in the fact that the apparatus installed ateach of thestations is a` uplicate of that installed at all the other stations.Therefore the special adjustment of each subscribers apparatus isunnecessary and the cost of installation is' thereby materiallydecreased.

Other -great advantages obtained by the' use of our present systemconsist in the fact that none of the currents used in the operationofthe selective apparatus are broken atA the substations,` it being awell-known'fact among those skilled in the artthat the use ofmake-and-breakcontacts at party-line su'bstations-give's rise to muchdxfliculty onl account of the oxidation and deterioration of suchcontacts due to the sparking caused upon the breaking of the current.

Our improved system presents a further advantage over those heretoforeemplo ed in the fact that the strengthof the selectingcurrents is notmaterial to the proper operationof the substation apparatus.

The objects of our invention are attained through the provisionzof adouble metallic.

lme, one side of which may be continuous throughout the length of theline, each subiscribers ap aratus .being desirably provided -with a brige connection therewith. The -other side of this metallic line may belooped in at each of thesubstations, one side of each ofsaid loopsbeingv connected with a art of the subscriber? s selective apparatus.

of the substations this loop may beprovlded with a normally opencontact; A art of the operation of the system includes t e succes; siveclosing of these loops, thereby buildingup this loop-linethrough thesucces'sivesub-y stations. The continuity of the loop-line is los teach.45 occur until t thereby attained., there being established by thisbuilding-up process two continuous metallic lines extending from thecentral station associated therewith to the farther end of the 5party-line.I --The circuits used in this build- .ing-upvprocess may beestablished, as desired, either through one of the lines in connectionwith a grounded return or through thev two lines themselves..

- `ro A further result of the proper operation of the. selectiveapparatus consists 1n bridging the desired. subscribers telephone acrossthe two metallic vlimbs of the party-line -as previously established.Normally each i 5 subscribers .station may be provided with a groundconnection, particularlyT if the ground- -ed return is used 1n thebuilding-up proc-7 ess previously referred to, a further result of thesetting-'up operation of the selective ap-l zo paratus being to breakthis normally grounded connection.

Our invention further introduces a new-.

andeHicient'lock-out system., it being impossible when the line is inuse by lany one party e 5 on the line forwany other party on' the sameline to either listen in or signal or in any manner disturb lthesubscriber who is entitled to the use of the line, and a still moreparticu# laradvanta' e-ofv` our lock-out system over 3o those hereto oreemployed resides in the fact that the said lock-'out feature is entirelyautomatic, it being aguinherent feature ofthe party-line systemritself,and no special provisions are necessary wit our system inorfdentosecure'thelo E feature.` x Some lo FA ost desirable Objects ofour .inv'entio/Il- ',are attained by the provision of.

selective apparatumfor thesubstations, the circuit breaking or changingoperations of 4o whichare accomplished aftera proper 'flow of currenttherethrough has ceasedthat is upon what might be termed its reversef'stroke. Many novel features are incorporated in the construction andmode of opera- ;o tion of this improved selective apparatus,

which, in addition to the other features of our invention, will be bestunderstood by reference to the accompanying drawings, in

which- 5 5 Figure 1 is a diagrammaticview showing thecireuitonnectiosemployed in the operaft/ion of oursystem/including acentral-station equipment which may desirably be used in connectiontherewith. Fig. 2 is a side eleva construction ofthe said selectiveapparatus.

In all ofK said views similar reference characters are applied to likeor corresponding parts. l

The precise arrangement of the central-station equipment employed is notpertinent to the present invention, it being merely necessarythatcentral-station apparatus-beprovided whereby currents of desiredpolarity may be sent over anydesired' circuits of the party-line. Wehave, however, shown a manually -operated central station equipmentsuitable for use in connection with our partyline system.

Since the circuit arrangements of ourv system, the sequence, ofelectrical connections made, and other features of the operationlthereof will not be readily ap arentwithout an understanding of the mecanical devices employed to carry outour invention, we shall vfirstdescribe the mechanical construction of the selective apparatus employedand thereafter trace the electrical circuits used in the operationthereof. Y 4

The selective. apparatus is mounted on a base 1, to which are securedthe horseshoe# electroma ets 2 and 3, the front endscf the cores of tese electromagnets ca the sheet-metal frame-piece,` 4. Carried by thestuds 5 5which extend from the frame-piece 4, is thehorseshoe-electromagnet 6, this electromagnet being provided with apermanent polarizing-magnet 7. A frameportion 8 is adapted topivotallysupport' the f armature 9 adjacent to thepole-pieces oftheelectro` magnet 6.- VThis armature isoperated only upon a flow of thecurrent. through theelectromagnet 6in al certain direction on account ofthe polarization of said armature causedby the permanent magnet 7. lAdetent 10 in the shape of 'a bent Wire is 'secured to the armature 9,the purpose of which datent will be hereinafter'more fully setfjorth.Near.

the center of the front framework ofthe deviceis provided-a'fxed shaft 11, upon which l are rotatably mounted various pieces of mechanism. `Thusrotatably mounted' u on the said shaft is provided the spur-W ee'l 12,

there being rotatably associa -d therewith a' ratchet-Wheel 13. ltWillbe n f'ticed'that the ratchet-wheel 13 has twice as many teeth asthere are spurs on the' spur-wheel 12. A

ratchet-pawl14 prevents the rotation of the ratchet and spur wheels in aclockwise direc- .tion.' Aweighted lever 1 5 is rotatably mount# ed uponthe shaft 1 1 just back of the ratchetnoi c/tion of a set of selectiveapparatus intended The upper aii'r'of th's'cross-bar 16 carries a x25`/'to be installed at a substation, parts being pivot-ed ratchet-pawl17, adaptedto engage broken away to more clearly reveal the optheteethof the ratchet-wheel13. l arma- .eration thereof. Fig. 3 is a frontelevation ture 1,7 is pivotally mountedto swing from of the same withother parts similarl broken the normal position `(shown' in Fig. 3) into65 away. Fig. 4 is .a View illustrating etails of alinement with thepole-,pieces of the electro- 130i magnet 2,

a stop 18 beingr provided to deter- 'mine the swing of the armature. IThis armature 17 carriesa downwardl fro'ectino' nin 19, so disposed asto engage a pin 20,projecting from the back of. the cross-lever 16. Thusupon the energization of the electromagnet 2 its armature" is drawninto'line with the polepieces, thus causing a motion to be communicatedthrough the downwardlyprojecting lever-pin 19 and the pin 2O to thecross-amr' 16 of the lever 15.

The rotary motion of thlslever mechanism will bein a clockwisedirection, suiiieientto draw the pawl 17 back. over one toothoi the.ratchet-sheet .13. contains the two ternnnas 36 and When a current hasstopped flowing through the elect-romagnet 2, the weight of the lever415 is sufficient to transmit power through the pawl 17 to theratchet-wheel 13, thereby turning it the space oi'4 one ratchettoothin acontra-clockwise direction, it being remembered A that on account oftheir rigid association the spur-wheel 12 willl rotate in correspondencewith the ratchet-wheel 13.

Referring'-now to the electromagnet 3, it will be seen that it also isprovided with a stop 21, limiting the motion of its swingingarmature-22, which in turncarries a lever-pin 23,'adapted to engage apin 24 on the'lower projectingarm of the cross-piece 16.. Thus anenergization of this lower electromagnet 3 will cause the weighted armof the-lever mechanism to rise` and upon its release to cause therotation of the ratchet-Wheelthrough the space 'of one notch in a mannersimilar to that- 'v to say, a temporary current either the electromagnet2 or theelectromag- A nets?) vwill cause a similar operation of theproduced by theelectroma net 2-that is lever mechanism and theratchet-Wheel and spur-Wheel associated therewith. A

A rotatable shaft 25 is provided with suitable bearings a d carries uponits outer end an exhausted -ass bulb 26,- containing merest illustratedin Figl 4, this shaft 25 is further provided with a tail 26',

1 adapted to be-actuated by the spurs of the -bulb ,to-be' tiltedbaclir'into its normal posi- A'wheel 12. 'A weightedv lever 28 tends tomaintain the mercury-bulb in a tilted or normal position. (Shown'inFig.'3.) It will be seen that upon the rotation of the s ur-wheelthrough the spaceof one ratchet-w eel tooth the tail 26 will be engagedby a spur ofthe spur-wheel 12to raise the said tail into its alternateositionas shown in dotted lines in Fi 4, t ereby causing themercury-bulb 2 6 to e tiltedinto its alt rnate position. (Also indicatedindotted ligles.) Itwill be seen', furthermore, lthat a e tooth willcause the disengagement ofthe upon the Weighted lever-28wil1fcause thetion, as shown in Fi 3.

Itshould be noticed here .thatfplatinum owing,through nd rotationl ofthe spur-wheel through thfe space of one ratchet-'A vmine.

Wires are sealed into the 'tube 26 in vsuch al a*way that the bulb andthe inclosed mercury form a tive-contact switch. .T he Contact 29 1s 1ncontact with the mercury in either of its alternate posit-ions, thecontacts 3 0 and 31 -being brought into Closed connection therewith whenthe mercury-bulb is in -its normal position, the'contacts 32 -and.3 ,3being bron ht into contact withthe common ter- 29 when theniercury-bulbis in its alternate or' abnormal position.

Referring nov.' to the second mercury-bulb 34, which is similari)7.mounted upon a rota.- tztbic sii-ait 35, it u iii beseen that this bulbwhich terminals are connected by the. inciosed mercury only when thebulb 34 is in'its alternateposition, (indicated in. dotted lines,) l

The normal disposition of this tail 40 to the spur vof the spur-wheeladjacent thereto is such thatthe release of the.detentcam39 by The dethedetent-wire 10 will allow the we'ehted'-le-- ver 41 to cause the tiltingof the bul l34 into its alternate or abnormal position, thus causing anelectrical connectionv between theterminals 37 and 36. Alotation ofthe'spurwheel, however, causes the engagement of a t e said tail,thereby rotating the bu "34 and its associated datent-cam 39 back 'intotheir normal position, where lthe detent-wire 10 slips over thecam-surface and thereu von catches the detent ed e of the .cam 39. .'-lus the bulb 34 is retaine in its normal positon',`

. (shown n Fig. 3,) except upon the actuation of the polarized armature9, whereupon the datent-wire releases the cani39,- thus permittin thetilting of thebulb;

he circuit connections 'of 'the selective api aratus arediagrammatically illustrated on ig. 3, Where it will be seen that aconnection is made between the binding-post A, tl1rough the Wire 42, tothe fuse 43 connections being made from this oint tothe terminal 29.511the bulb l26 and to t e terminal 36' `in the" bulb 34. electricalconnection is made between the binding-.postG'., through the wire 43,'to the electromagn'et 2', the said electronia'gnet`be--ingconnected'inlseries, through 'thejttfire 4.4, with thegelectifomagnet6 fromwhich the remannng connection is made`thfough`the*wire 45,- withvthe tei-mind so in the Bulbzcf.' Cons nection'is made/from the Vbindin,1f' post B,

spur thereof with the tail 40, so as'to de ressloo the bulb 26. shown,between the binding-post' A and'the through-the Wire'46, to thebinding-post T, lfrom which 'al Wire 47 leads to the electromag- .net 3,thefr'emaining .terminaljthereof bein connected bythe 'wire 48 with thetermina Connection is made, as

contact.33. A wire 49 connects theI binding- )ost T with d the terminal37 in the bulb'34. he contact` 3'1 in the bulb 26 is connected with thebinding-screw '50, r'o'm'whichga con-A nection is made'wit'h-thecontact. 51 of a 'key' 52. (Shown only in the diagrammatic view,.

Fie. 1.)

-laving thus described theselecting mechconnected with any desirednumber-of substations',- 'Infthe diagrammatic figure, however, Lwe haveshown vvbut two 'such substations- 201' and 202; connected with theline, it

being understoodthat the remaining substa- -tions 'are ,connectedtherewith in an exactly similar.l manner. `Onaccount of theimpossibility of satisfactorily illustrating in diagrammatic drawing?all the mechanism necessary to carry outthe operations in our sys" temwe have merely'atte'mpted to illustrate. in the selective appara tustheelectroma ynets and' the `electrical contacts controlledl t'ere-' by.'Referring more' articularly to. Fig.'1',.

we haveshown a meta lic telephone-line con-.5 l

lwnly when a, current flows in the -proper disist' vor 'the lineb,"which runs straight through `from the exchan eto all of thesubstations without a brea, and the line a,v which is desirably loopedinto. each ofthe sub*- stations.... The line-wire aznay be connectedwith `-a ti -spring y53 andthe line-wire Zr withthe' s ecirc-spring 54of a spring-jack at the central station. A contact 55 normally makesconnection Withfal'ong jack-sprin and is connected througha line-drop 56an A the battery 57 with the ground Gr. In the further description ofFig. 1 ,it should be' 36 in the bulb '34.

borne in mind that merel the circuit .connections are indicated and t atthe electromagf nets shown correspond with an-electromagnet "havingsimilar reference' characters in the. .other figures. It4 shouldurthermore be bornein mind that the-circuit changes caused by thee1ectromagnets2 and'3 are not,

brought about except upon the reverse stroke of the mechanismoperated'thereby. ,Y Tracin the' circuit from the-tip-sprmg 53 through te line-Wire a, we come to the' binding-post A, from which it will beremembered a connection was made with the terminal contact 29 in thebulb 26 and with the terminal such a position that the terminal 29 is-connected,

ymeans of the mercury,'with the tere Normally the bulb is in' thevarious conditions of operation to which V`a party-.line system issubjected. First, taking that condition under which la party on aparty'-` line--for instance, at' station 202- wishes to call central andremember' that the circuit between` contacts and 37 is normally open andthat connection is. normally made between contact 29.and contacts 30 and31 the subscriberat station 202 makes .connection-between the. key 52and thecon- -tact 51.- IfIe thereby closes'the following circuit: fromcontact 51 tovcontactfBl, tocon-' tact 30,- to electromagnet `6,through, wire 44, to electromagnet 2, to binding-post -Gt ground G,through ground -to battery 57,' to dine-drop 56, to contact 55,to-spring 54, to

line=wire 5,to bindin bo'st B atsubstation 202, 'to bindin -p'ost,-tokeyf52. Thus we have traced t e'circuit which will energize the twoelectromagnets 2 and 6, it being re-4 membered'th'at the electromagnet 6is provided With a polarized armature operated rection through' -the'the ground, such t4 at the current fiowing' throughany electromagnet 6located a't any vof thexsubstations on the line will fiow through' thesaid'electromagnet in sucha di# reetiomas to operate the'armature,thereby releasing the-trip, which permits a' tilting of the bulb 34 tomake connection Abetween thecontacts 36 and 3 7. The energization of-theelectromagnet 2 While this current Hows will. have caused the operationof the lever mechaniSm 15 16. i ,y

' U' on the cessation ofthe current-flow the ratcl 'et-mechanism .willbe operated by the reverse'stroke of the lever mecha nism, through whichthe connection of the terminal 29 from that'with the contacts 31 and 30is changed to a'connection with the'contacts 32 and 33'.

.The telephonie a paratus 58, installed at substation' A202, wil therebyhave been con- IIQ u l 5 i vnectedin brid e across the metallic limbsofthe tele hone'- ine, a condenser59 being'connected 1n thetelephone-circuit to prevent -a lowsof. battery-current therethrough. lt

will be seen, furthermore, that through the depression of this key 52and the ensuingo erationof the mechanism controlled by the eectromagnet2the -loop in'the line-wire a, connected inat station 202,has been closed, thereby affording acontinuous electrical path throughthe line-Wire a, so far as the-substation 202 is concerned, it beingapparent that thisnormally open loop is electrically closed vby. theconnection of the Contact 29 with the`v circuit ynormally includes theline-drop 56 andthe battery 57.

"flt'will be seenfthatthe'tip-strand 61 completesfitscircuit partiallythrough a Spring 62 which in its normal position makes contact l' With'-the ,remainder ofthe tip-strand.' `The sleeve-strand 63'is likewiseconnectedwith a key 64, -whichfnormally is connected withthe remainderof the operators usual cord-circuit. The operators cord-circuit need notbe particularly described, .in that it is fami-liar to'those skilled inthe-art. It is provided-w-iththe usual and listening key 65 and thelassociated generator and op- Aerator's telephone set." .Bridged acrosst e cord-strands is the disconnect signal-relay 66. The calling-plug'67may desirably have keys 68 and 69 connected in circuit therewith, theoperations of these keys being hereinafter.

more fully set forth.'v l

After plugging. into the answering jackI the operator depresses the key62, thereupon -making a connection between the tip of the plug 60 andthe conductor 70 of the polechanging circuit71. This pole-chan lring ar--rangement cbnsists, essentially, of a attery 72,-Which by propermanipulation -of the springs` 73 and 74, may haveeither of its poles, asdesired, connected with the condn'ctors 70 or 75. The operatormanipulates the pair of springs 73 a number ef times, at least'as great'asrthetotal number of stationsl connected. withthe calling arty-line.-She thereby closes a circuit, Whicxii 'maybe traced as follows: fromlthe positive pole of the battery 72, through the upper spring 73, toconductor'75, to ground G,there being no circuit connection between theconductor 75 .andthe key 64. The circuit maybe traced through the groundtothe binding-post G of the substation 201 thence through thecorregionding-'electromgnet 2 and the lelectro- 4 inagnet 6,'to contact30, to cont.act 29, to bini'- ing-post A, to line-Wire a, to tip-spring534:1?0

owing through" tip-strand 61, to spring 62, to conductor 70,

to the lower spring 73, to the negative pole of the battery 72. Therewill be no such c ircuit formed from the ground of subscriber A202 tothea, Wire, becausethis circuit would be necessarily traced through aconnection between contacts 29 and 30, and itwill be remembered thatupon-the depression ofthekey 52 ats'ubstation 202 the operation of theelectromagnet 2 caused a separationof'the said contacts 29 and. 30. A,similar circuit as thttgmdffop substation 201 conld'not be tracedfo thesubstationf203 and the remaining ubstations upon .the line, for thereason t at the circuit through the a wire for these m reremotestationsis not completed throng 'the loog entering the nearer substation 201until t e operatlon of the mechanism caused by the current-flow throughthe electromagnet 2 of substation 201, it being rememberedthatthe changeof connection Aof the contact 29 is not brought about until the'breaking of thissettin -up current at the' central station. vIt shou dbe -noticedffur- ".thermore, .that in this setting-up operation the--key 73 connectsthe battery 72 with the apparatus in such a directionthat the actuatlon of the yarmature associated with the electromagnet 6is not bro ht about. Therefore upon vthe operation o the key73 none ofthe switches associated with the electromagnet Gaisoperated.

The first' closure of the springs' 73 with their associated contacts andthe 'subsequent release thereof causes the oundconnecton I G to bethrown ofi from t e substation'ZOl, and at the same time' theloopthrough this substation is. closed by the connection of contacts'29and33.

' The second manipulation of the key 73 would cause a. similar change inthe Acircuit connections at tsubstation 202 had not a simi- 'lar chanebeen already brought Yabout through t e agency of the electromagnet 2,due tothe manipulation of thekey 52, Vlocatedat s'ubstation202.Thereforethesecond -manipulation of the springs 73 causes an operationofthe instrumentalities at the third substationx203., corresponding'with the operation at substation 201, hrought'about by the first maniulation of the-sprin s 73. Similarly, eaclii key 73 builds up theline-wire a tothel next 'succeeding substation, at` .the same timethrowing off the ground connections for the successive substations.4Thus. after a number of manipulations ofthe key 73, corre.- sponding tothe number of stations on a party-line, all the grounds have -beenthrown off and the-.subscriber 202 is alone bridged across the metalliclines a and b. The o era tor thereupon releases the'key 62, whic hasbeen depressed during ythese bperations, whereupon.hercord-circuitisconnected with IOO IIO

successive manipu ation of the.

the metallic line, across which the substation a paratus is bridged in amanner familiar to t ose skilled in the art. i

The subsequent operations of ascertaining the subscriber with whom`conversation is desired-and the callinscof` the called subscriberneednot be described.4 A It may be well to here point out the fact thatafter the vbuilding `up of the fline, as above described, all the' lo,ground connections have been thrown ofi, so that no othensubscrlber onthe same lline can secure the closure of his circuit between con-itacts36 and 37which, it will 'be seen, is absolutely necessary in orderto connect his telel phone instruments with the line. It is thus thebulbs 2 6. Upon the completion oftheo conversation between substation202 and the called' subscriber the operator will receive adisconnect-signal, dueto the current-from a ringing-generator. -Beforeremoving her plug from t e j ack it is necessary that she restore:

all of the subscribers selective apparatus-to lits normal position. Thisshe does by sending a battery-,current over the two limbs a andbofthetelephone-line. It will be seen 'that in the alternate or built-upcondition of the selective a paratus all of. the electromagnets 3 arebri ged across the metallic lines, Athe electromagnet 3 being normallyandcontinuously connected with the b wire and in the valternatecondition being connected -.throughcontacts 32 and 29 with the c wire.

Referring more particularly to 'Figs 2; 3, -end 4; it will be seen thatthe energization of this electromagnet 3 will cause upon the-re- -versestroke a one-notch rotation of the spur- 5o- Wheel 12. The tail 26 willbe in its'alternate position,as best shown in dotted lines inl Fig.

4. Thus upon the forward impulse of the spur-wheel the spurtooth willdisengage the ttail 26', thereby allowing the bulb to drop I 5'5' backinto itsnormal position. Similarly, the.

impulse imparted to the spur-wheel after the energization of theelectromaghet 3 will cau seaspur of the wheel 12 to depress the tail40,

thereupon raising the detent-cam 39 to a A6c point where the detent 10can retain thebu'lb m its normal position. Theroperator sends thisrestoring-current over the two limbs of the. metallic line by depressingboth of the keys 62 and-64 and 'thereupon operating the 65 springs 73g.Thus the battery 72 is` connectdesires to'calll a 'given substation upona three, 4and four upon the-line. It will also be l reverse direction,thereby causing. the operaed through the cord-strands 61 and 63 with themetallic line-Wires. Uponthe resteration 'of the'selective apparatus theoperator .withdraws her plug from. the jack.

It will be seen that in thatstation or in those stations in which thebulb 34 has been tiltedirom its normal position-the restoringmagnet 3when energized by the restoringcurrent from the central station willrestore the said bulb Sito its normal position, and in 7 5 all of thestations the actuation caused by the restoring-magnet-will restorel thebulbs 26 back to their normal position:

Coming now v"to the case in which central given party-line, the operatorfirst plugs into the-jack corresponding to the said party-line. Shethereu on depresses the ke 62 and manipulates t e springs 73' anumber'of times, v one less than the 'number of the substation 'to 8 5be called upon the part -lin'e. Thus if the operator wishes to call t 'esubscriber whose station' the fifth remote from the central station shewill manipulate the key'73 four times. The-circuit set up by themanipula- 9o tion-of this key has been previously traced, it

bein'g'remembered that a single operation of the said sprin s causes thebreak m theloo at the first suliscribers station to be close alsothatthe same manipulation throws off the ground connectiony at the firstsubstation. The three succeeding manipulations, 'off-this; keywill thensuccessively produce a similar change in theapparatus at substationstwo,

`IOO 'remembered thatl the'. manipulation of the springs 73 does notpermit 'current hollow.

rough the electromagnet 6 in such; a direction as toattract thearmatures A9;; However, after' four manipulations of the springs- 73 thelifth manipulation is ofthe springs 74, whereupon the selecting currentis .sent through the fifth subscribers apparatus'in the tion of hispolarized armature 9, Thus the fifth subscribers telephone [setisbridggedV -across theline. At the same time 'or immei. diatelythereafter the break in the line 'a't his substation-is buil-t up.-After this manipulation of the. springs-74 the' succeeding currentv 1i5 impulses are sent out by manipulations of the springs 73, thus causingthe remainder of the substations on the .line to' have' their groundconnections thrownI oil. Substation ve' is then alone bridged across theliiie in condition' to carry on conversation with a -calling -subscrier, who, it may be assumed, has previously been connected with the otherside of the'operators 'cor'dcircuit. Under these circumstances 'the lineis b uilt up in the same way 'as it wasfunder the condition in which thesubscriber-on the panty-line was calling, with theexception that insteadof the actuation oithe armature 9 .being controlled by the key 52 it iscontrolled -by the central opA 13d -Iro vto

erator bvthe reversal of the direction of th siredconnection.

deed, does not know which particular station is the calling station. ona party-line; but

, when a calling subscriber asks for a connecltion with anothersubscriber. on the' same the' callin are locate v ing up "abroken line,she is enabled to know?? which of thel building-up impulsesare to bep'arty-lineit becomes necessary for the opera-j tor to know thesubstation-number of bothV and thecalled subscribers who?I on the sameline. Thus in build# reversed in direction, so as .tofonnect the twodesired subst-ations with the line-wire b.' l

It-will not. be necessary for a proper understanding of .the operationsto vtrace the' circuits employed, it being apparent that the operatorupon receiving a.- line-signal will build upthe broken line, as usual,andthen inquire for the connection desired bythe call-.

in subscriber. Upon learning 'that the c `led subscribers station islocated on the same party-line as that of the calling sub-` scribr, theoperator will first restore the partyline to .its normal condition, ashas een previously explained and will thereafter send outthe setting-upimpulses, as hereinbefore explained. In building up the line, however,impulses inreverse direction will be.

-employed corresponding in number-with the two substations to beconnected for conversation. Thus upon buildin f up the line the tworequired subst-ations will have their tele-v phone instruments connectedby the corresponding'reverse impulses with the line-wire by Therestoration of the mechanism connected with the party-line upon thecompletion of the conversation is accomplished as heretofore explainedfor the other conditions of oper ation.

Thus it will be seen that our invention rovides a partyline telephonesystem w ich overcomes the defects in existing systems and at theSametime introd uces' material advancesover the systems of the priorart.

Since theselective apparatus employed in our lsystem is not dependentupon the strength or polarity of the currents employed nor upon what'maybe termed marginal currents,`the instruments are not delicate in theiradjustment, and therefore subject to false operation. The instruments,furthermore, do not depend upon synchronous operation, and thereforecannot introduce difficulties by getting out of'step one with another.-The selective apparatus is not normally bridged lacross theselcctinU-circuit, as

Under normal conditions v the central 'operator does not inquireand, in#

inmanypartyd ine sys tems, whicl thereby i troduce dihculties on accountofthe different resist-ences encountered. by currents flowing fromthe'central station to various substa l tions. In this connection it`will be seen that since only one of the selectingeicetromagnets isoperated at a tlmeonly asmall amount of.

operating-current is necessary.

In regard to the bridging of the restoringelectromagnets across the lne,which are then o erated `in parallel,` vit may be pointed outl 't at iffor anyreason thecurrent strengthia not'suiiicien't to operate theinecha'nismat ail of the stations only those restoring-magnets which arenot roperlyoperated remain in the circuit.v Tlierefore -a. secondrestorin impulse, on account ol the largely-decrease number ofaths, issure-t operate any of the magnets which fail-'f-operation on` the firsti y ulse.. Y 'ix'l'llhe mercurytubefswtgehes which are.

preferably-employed. are of decided advantage over switches heretoforeemployedv on account of vthe fact that the contacts are not"subjecttodeterioration on'account of their exposure to atmosphericconditions,- and our present system proavides a further great aid-'vantage, which, ndeel,would"be present whetheror not 1the merc-switcheswere employed .in that theselecin'g-eurrents are never brokenthe switches'at the substa-- b. tions. While the circuit connectionsare, ini deed, changed at the'substations, these cir.

cuit changes are always made-npn the reverse stroke of the o eratingmechanism when.

no currelnt is actua ly flow: therethrough;

'Thus all the undesirable res ts caused by a IOO frequentlyfrecurringelectric sparkbetween switch-contacts are done away with.l

It will be seen that our stem provides what may be termed a double-lock-out feature in that upon receiving a signal at the central stationthe o'perator plugs into the lineej ack, whereupon the ground connectionthrough-the line-drop is broken. This of ,course at once prevents allthe subscribers;-

except the one .who has previously depressed his key 52, from gettingthegrcund connection through the battery 57, which is necessary in ordeito` operate their switches c'oi necting in their telephone apparatus.thev broken line has been set up bythe cen? traloperator the connectionsbetween con;

.tacts 30 and 29 are 4broken at' all of the'sub stations. This of courseintroduces a second break inthe circuit necessary for a subscriber toget his telephone apparatus connected with the line. Thus by this doublebreak in the circuitwe introduce what may be termed a double lock-out"`feature.

In connection with the lo'ckoutfeature our system provides a distinctadvantage in that the line. and all the ap aratus .connected After yizotherewith are directly un er the .controliof the'central operatoralone-that is to say,

p the operator her power togive I 4o i A Our invention maybeadvantageouslv employed in connection with a metallic tolllineconnection only to those subscribers Whom she desires 'to connect, andshe is' enabled at any time to out off any subscriber who 1smonopolizing the line. This is also a desirable '5 feature when aparty-line is also used for tollic improved system is an exact line puroses, it being customary to alloiv the toll-line business to supcrccdethat of the local substations. i

The apparatus used in the o eration of our duplicate at all of thesubstations, the substation selecting apparatus not being set oradjustedin any way peculiar to its osition or number on 'the 'party-line, and,1n eed; the suhstations are notindividually adjusted even to the extentof a resistance-coil. In so far as the instal- Alation'oi? our system isaffected by present ex isting apparatus it a Wortlyvfeaturenineconomical installation that any form of telezo phoni or. signaling'apparatus whatsoever may be associated ywith our selective devices.

its fvillbe apparent from the foregoing description of one embodiment ofour invention,it will be seen that the subscribers tele# hone apparatusis normally disconnected rom the-telephone-line, it being then onlynecessary to connect with the line of that sub-` sdribers. telephone setwhich is .to be rn.

played for conversational purposes. This f ca- 3o ture presents adecided advantage over those systems in which all of the telephones arenormall'y connected with the line and all of which must be disconnectedtherefrom save that telephone'which is tobe 'used inconversatiomIncidentally'it4 might be pfointedout that the condensers 59 arenormally disconnected from theline. They are therefore not subject topunctures due to lightnin discharges, which is an iinpolrtant factor inlie operation of a long party-line.

ruiming through and betWee'n a number of 'central sta-tions, it 'beingnow a lcommon practice for an operator-say at a principal office at theend of a tollline-to have a connection only to the first of a series .ofcentral stations connecting therewith. In order to'v secure connection,With a more remote cen- 4trallstation, it is necessary for tlie operatorat the principal sltation to ordertlie operators at the subcentrastations to Nmake the`connections intervening betWee-n'the successions'of the otherwise continuous metallic line. Our invention as applied tosuch toll-lines enables the principal o erator to have control .over theconnecting evices attlie'subcentral stations, .whereby she can secureconnection with any desired central station.

While we have shown and particularly described one preferred embodimentof our'.in

vention, it will be evident that many changes and modifications thereinmight-profitably employed Without departing' from the" spiritof ourinvention. We therefore do not `65 Wish to limit ourselves totheprecisedisclosure herein set forth; but,

Having described our invention, We claim as new and 4desire to secure byLetters 'Patentl v 1. lilie combination with a centralstation, of a linerunning from.said central station broken at a series of substations,electromag# 'netic mechanism controlled romthe centralstation'adaptedto'build up a non-inductive electrical path through said 'broken ine toanydesired substation, electric signalingapparatus 'at each ofsaidsubstations, a second ineconnecting all of said substations with thecentral station, electromagnetic mechan.

ism lat' each of said substations controlled vfrom said central station'adapted to connect said signaling apparatus in circuit with said.

lines,'and means at each ofsaid substations affording 'a secondarycontrol over the electromagnetic connecting apparatus at thecorresponding. substation, substantially as de-A scribed. i t f 2. Thecombination with a ce'ntral station,-

of 'a line running from said central station broken at a seriesofisubstati'ons, electromagnetic mechanism controlled from the centralstation adapted to build up a non-.inductive circuitthrough said vbroken1ine to any desired substation, a return-circuit from said substationsto said `central station, velectric 3. The combination with-a centralstation, A

of a line running from said central station broken ata series ofsubstations, a return-circuit from said substations to said centralstatioii, electric signaling apparatus at each of said substations, asecond line connecting alll of said substations with the centrallstation, electromagnetic mechanism at eachof said substations controlledfrom said central station adapted. to connect thesaid second line withthe signaling :apparatusat any vof said substationaand means at each ofsaid lsubstations affording a secondary control over the electromagneticconnectingap'paratusat the corresponding station,- su described.-- t

.4.V The combination with a central station,

of a line running from-said cential station brokenat 'a' seriesof'substations, electromag#A *netic mechanism controlled'rom thecentrall station' adapted' `to build up a n onfinductive -stantially as'circuit through saidbrokemline to any de sired substation, otherelectromagn etiumech anlsm controlled frogn said central stationnalingapparatus ateachof said substations,

adapted to break saidfelefctric circuit at said substations, areturn-cncuitirom sain' substatlons -to'sald central station, electricsiga secondline connecting all of said substatio'ns the central station,electromagnetic mechanism' at each of said substations controlled fromsaid central station adapted to connect the said second line With thesignaling apparatus at any of said substations, and means at each ofsaid substations afford:- ing a secondary controlover theelectromagnetic connecting apparatus at the corresponding station,substantially as described.

5. In a selective partydine system, the combination with switchingmechanism comprising a mass of mercury for making or breakin electriccircuits, of electromagnetic 'means or actuating said mechanism, andmeans for causing current to new through said electromagnetic means, theop eration et, said switching mechanism being accomplished yWlroiljyfupon the cessation of said current-flow,

- substantially as described.

' stantially as described.;`

' `of a line runningfrom lsaid central station 6. ne combination with acentral station,

of aline running iromthe said central stationl broken at a series ofsubstations, electromagn 'metio-mechanism adapted to be actuated bysuitable electrical impulses to build up a noninductivecircuit throughsaid broken line to any desired station, 'other electromagneticmechanism adapted to be actuated bye suitd able electric impulse tobreak` said electric circuit at said 1substationa return-circuit vfromsaid substations to said centralustation,

electric signaling apparatus at each of ysaid substations, a second lineconnecting all oi. said substations with the central station,electromagnetic mechanism` at. each of said substations adapted to beactuated by an v.electric impulse oi" suitable polarity to connect thesaid sedon'd line `With the signaling apparatus at. any of thesubstations, means at each of the substations affording a secondarycontrol @fthe electromagnetic connect-4 ing apparatus 'atthecorresponding station and means proydedat the central' stationwhereby the? operator-may control said electromagnetic mechanism bycausing suitable electric impulses to'liowtherethrough, sub

7. The combination with a central station,

broken at a series of substations,v neutral electromagnetic mechanismcontrolled from the central station adapted tobuild up a non-inductiveelectrical path through said broken line to any desired sullstaftioneleptrio signala aratus at eac 'o sai su stations, a loudplineconnecting all of said substations lith 'the central station,electromagnetic trolled from said centralstation'adapted to with two ofsaid lines, an means at each oi said substations affording a secondarycon trol -overthe electromagnetic connecting a paratus at thecorresponding substation, substantiallyits described.

8.. The combination With a central station, ofa line running from saidcentral station broken at a series of substations, electromagneticmechanism controlled from the central station adapted to build up vanon-inductive electrical path through said-broken line to any desiredsubstation, a return-circuit from said substations to said centralstation, electric signaling apparatus at each of said substations, asecond line connecting all ol said substations With the central station,electromagnetic mechanism at each of said substations controlled fromsaid central station adapted to connect one of said lines with thesignaling apparatus at any of said substations, 'and means at each ofsaid substations mechanism at' each of said substations con- 6 adordinga secondary control over the eleci tromagnetic connecting apparatus atthe corresponding station, substantially as described,

9; The combination With a central station, oi a line running from said.central station broken at a series of substations, electromagneticmechanism controlled from the central station adapted to vbuild u anon-inductive electrical path through said broken line to any desiredsubstation ,other electromagnetic mechanism controlled from said centralstation adapted to break said electrical path at .said substations, areturn-circuit from said substations to said central station, electricsignaling apparatus at each of said substa tions, a second lineconnecting all of said substations With the central station,electromagnotie mechanism at each of said substatons IOO controlled fromsaid central station adapted Y to connect one of said lines with thesignalingv apparatus at any of said substations, and

means at each of said su'bstations affording a secondary control overthe electromagnetic connecting apparatus at the corresponding station,substantially as described.

10. The combination with a central station, of a line running from saidcentral station broken at a series oi substations, electromagneticmechanism controlled 'from the central station adapted to build up anon-inductive circuit through said broken line to any desiredsubstation, a return-circuit from said substations t0 said centralstation, electric signaling apparatus at each of said substations, asecond line connecting all of said substationswiththe 'central station,electromagnetic mechanism at each of said substations controlled fromsaid .central station adapted to connect` said signaling apparatus incircuit with two ci said lines, and means at leach :said substaticna IIOaffording al secondary control over the elec- 'tromagnetic connectingapparatus at the corresponding station, substantially as described.

11. .The combination withacentral station, v Aof a linerunningffrom=said central station,

broken at .-a seriesofzsbstations, a return- .circuitiroxn saidlsubstations to -said central station,.electr1c signaling apparatus' ateach cffsaid substations, a Second line connecting all of said.vsubsi'latioils'with y.the central station', electromagnetic mechanismat each of said substations controlled from said centralI stationadapted to connect said signalingapparatus in circuit 'Withtwo of saidlines, and means-at each of said substations affording a secondarycontrol over the electromagnetic connectingv apparatus at thecorresponding station, substantially as described.

12. In a selective party-line telephone system,'the combination with acentral station, of a line Arunnin therefrom to a series ol. substationsnormal ybroken at cach of said substations,signalingl apparatus at eachof said substations normally disconnected-'from said operator may.connect the signaling apparatus at a plurality of said substations invcircuit simultaneously with saidnfbroken line,`

substantially as described. l

' 14. In a selectiveparty-line'telephone system, the combination with acentrall station, of lines running from the central station to a vseriesof subStatiOnS, one of said lines bein normally broken at eachsubstation, sigf4 na ing apparatus at each lsubstation normallydisconnected from said broken line, and means controlled from eachsubstation and from the central station, whereby the correspondingsignaling apparatus may be connected with the broken as described.

15.l In a selective party-line system, the combination with. a central"station, of lines' 'running 'from the central station to a series ofsubstaticns, one of said lines being normally broken at each substation,signaling apparatus at eachvsubstation normally disconnected from saidbroken line, and means primarily controlled from the central stationwhereby any substation signaling -apparatus imay be connected with thebroken line and lsecondarily controlled from each substation,

whereby the correspondin signaling a paratus may be connectcdwit thebroken ine, substantially as described.

16. In a selective party-line System, the combination' with a centralstation, oflines' running from the central station to a series ofsubstations, one oi said lines being norvmally broken at eachsubstation, signaling apparatus at each substation normally dis-'controlled from each substation, and from the central station, wherebythe corresponding signaling apparatus may be connected with the brokenline, substantially as de scribed.

17. .In a selective'party-linesystem, th combination with a centralstation, of lines running from the central station to a series ofsubstations, one of said lines being norme, substantially lconnectedfrom said broken line, and means l mally broken at each substation,means for Y building up lsaid broken line through any number oil? saidsubstations, signaling appa ratus at each' substation'normally disconnected from said broken line, and means v'controlled from eachsubstation, and from the central stati-onf whereby thecorrespondingsignaling apparatus may be connected with said brokenline,'substantially as described. In witness whereof weliereuntosubscribe our naines this 6th day of October, A. D. 1902.

'ARTHUR F. POULE.I

` FRANK B. HALL.

l/Vitnesses:

MINNIE K. COCHRAN, LANDY Srsson.

